Tension roller devices of this type are generally used to maintain tension permanently on the distribution belt within a specific range.
A first type of tension roller device is known from document FR 2 920 851, comprising a pulley, a roller bearing on which the pulley is fitted, and an eccentric hub which supports the bearing. The device also provides a shaft to support the eccentric hub, a securing plate for fitting of the device on the associated engine block, and a torsion spring which is fitted between the securing plate and the eccentric hub. The device also comprises a spring support which is interposed axially between the torsion spring and the securing plate. The support makes it possible to ensure radial centring of the torsion spring.
A second type of tension roller device is differentiated only by the absence of the spring support for reasons of axial compactness, or cost. However, with this type of device, the radial centring of the torsion spring relative to the securing plate is not ensured. Radial displacement of the spring can then take place and give rise to premature wear.
The objective of the present invention is to eliminate this disadvantage.